Dual terminal insulator



Feb. 27, 1962 R. H. PREISER ETAL 3,023,268

DUAL TERMINAL INSULATOR Filed NOV. 25, 1959 2 Sheets-Sheet 1 If fi 2 Mg M fz-zrE'nfars SG li D, Kaiours 2! H175! 3,023,268 DUAL TERMINAL [NSULATOR Ralph H. Preiser, James J. McNally, and Joseph D. K- towski, Pern, Ill., assignors to Electrical Utilities Company, La Salle, 11]., a corporation of Illinois Filed Nov. 23, 1959, Ser. No. 854,758 2 Claims. (Cl. 174-153) This invention relates generally to a new and improved terminal assembly for use with different types of electrical devices such as a capacitor, a transformer, and the like.

In the past, various types of terminal insulators have been used for carrying terminals on a cover plate. The prior types of terminal insulators have been disadvantageous since they have had a tendency to rotate relative to the cover plate on which they are mounted when abnormal torque is applied thereon. When the cups are rotated a short circuit or an open circuit either internally or externally of the electrical device on which the terminal assembly is mounted, frequently occur. This rotation may also result in the loss or destruction of the hermetic seal between the cover plate and the terminal insulator or connector. Where the cups are rotated it will be appreciated serious loss may occur since human lives as well as valuable property may be thereby endangered.

According to the present invention, a new and improved non-rotating type of a terminal insulator has been developed which comprises a one-piece dual terminal insulator. The one-piece dual terminal insulator is comprised of a pair of cups joined together by a linking section which is formed integral with the cups from a suitable insulator material. This linking section provides means for preventing rotation of the cups relative to the plate so that the former difiiculties experienced in the use of the prior types of insulators have now been overcome. No longer will there be any likelihood of a short or open circuit or loss or destruction of the hermetic seal where the dual terminal insulator is prevented from rotating.

An important object of the present invention is to provide a new and improved one-piece dual terminal insulator which is adapted to resist rotation relative to a cover plate when it is mounted on the same.

Still another object of the present invention relates to providing a terminal assembly which will not be as likely to break down as a result of a short or open circuit or a loss or destruction of the hermetic seal.

A further object of the present invention relates to a new and improved terminal assembly including a onepiece dual terminal insulator which may be economically manufactured at low cost on a large production basis.

Still another object of the present invention is to provide a new and improved terminal assembly whose component parts and exposed adjacent metal parts may be more readily cleaned, painted and the like.

According to the features of the invention there is provided a terminal assembly for use with a capacitor, a transformer, and the like and which includes a one-piece terminal insulator having cups provided with rounded bottoms to permit the exposed metal parts on the device on which the one-piece dual terminal insulator is mounted to be readily painted, cleaned and the like.

Still another general feature of the present invention relates to the manufacture of a new and improved onepiece dual terminal insulator comprised of a pair of bushings which have means integral therewith to join the cups together to prevent rotation of the cups with respect to one another.

Other objects and features of the present invention will more fully become apparent in View of the following detailed description taken in conjunction with the accompanying drawings illustrating therein a single embodiment, and in which:

FIGURE 1 is an end view of a terminal assembly mounted on an electrical device such as a transformer and the like;

FIGURE 2 is a fragmentary side elevation of the terminal assembly shown in FIGURE 1;

FIGURE 3 is an enlarged fragmentary vertical crosssection view taken through the terminal assembly with portions of the fasteners shown in elevation.

FIGURE 4 is an enlarged exploded view of the elements comprising the terminal assembly, as shown in FIGURE 3;

FIGURE 5 is an enlarged fragmentary cross-sectional view similar to FIGURE 3 only showing a modified terminal assembly; and

FIGURE 6 is an enlarged fragmentary cross-sectional view similar to FIGURES 3 and 5 only showing still another modified terminal assembly.

As shown on the drawings:

The reference numeral 9 in FIGURE 2 indicates generally an electrical device of any suitable type such as a capacitor, a transformer, and the like. For the purpose of the present invention, the device has been interchangeably referred to as a capacitor and as a transformer. A cover assembly 10 which includes a terminal assembly 10' is carried on the electrical device or capacitor or transformer 9.

Briefly, the cover assembly includes a one-piece dual terminal insulator 11, a pair of bushings 12, 12, an oval cover insulator 14, an oval metal cover plate 15, a pair of terminals 16, 16, a pair of pins or fasteners 17, 17 and a pair of washers 18, 18. The terminal assembly 10 includes the insulator 11, the bushings 12, 12, the terminals 16, 16, the pins 17, 17 and the washers 18, 18. The following description will relate the matter in which the aforesaid elements of the cover assembly coact together with the novel one-piece terminal insulator 11, according to the features of the present invention.

The one-piece dual terminal insulator may be com prised of any suitable material and as illustrated is made of Du Pont Zytel #103 to resist chemical damage due to cleaning practices used prior to the zinc plating of the capacitor 9. The assembly 10' is comprised of a pair of cups 11a, 11a which are linked or joined together by a connecting or linking section 11b between the cups in the form of a figure 8 which linking section 11b is integral with the cups 11a, 11a. Each of the cups has a terminal socket area which is adapted to receive one of the terminals 16. The cups are each provided with bushing cup passages 11d, lid in which a bushing shank portion 12a, 12a is adapted to be disposed when it is in assembly with the cups 11a, 11a. The cups 1.7m are provided with upper and lower insulator or cup edges or shoulders He, He and 11 11 which are disposed on axially opposite sides of the cup passages 11d, 11d. The lower edges 11 11 are beveled to permit the material of the bushings to be displaced as will be further described.

In the assembly of the components of the terminal assembly 10, each of the bushing shank portions 12a are telescoped through one of a pair of cover insulator openings 14a, 14a and through one of a pair of cover plate openings 15a, 15a defined by annular turned flanges or collars 15b, 15b of the cover plate. The insulator 14 and the plate 15 are supported on the bushings 12 by means of bushing shoulders 12b, 12b. After the bushings 12 have been assembled with the cover insulator 14 and the cover plate 15, the bushing shank portions 12a are telescoped into the bushing insulator passages 11d with portions of the bushing shank portions 12a being disposed within the insulator socket areas 110.

Shank pin portions 7a, 17a are then telescoped through terminal pin passages 16a, 16a provided in base terminal leg 16b, 16b. This sub-assembly is then guided into the socket areas 110 of the cups 11a, 11a and the pin shank portions 17a, 17a are extended axially through a central tubular bushing passage 12c, 120. Each of the pin shank portions 17:! when assembled with the bushings 12 extends the full length of a bushing shank portion 12a and extends into enlarged bushing socket areas (or is disposed adjacent to bushing bottom areas) 12d, 12d provided on enlarged bushing head portions 12e, 12a.

When the components are assembled in preliminary relation as described above each of the enlarged head portions of the pins 17b is engaged on top of the base terminal leg 16b and terminal prongs or legs 16c extend away from the associated enlarged pin head 17b as well as away from the terminal socket area 110.

To maintain the components of the terminal assembly 10' in assembly together, the ends of the shank pin portions 17a are riveted at 19 over the washers 1b which washers are mounted within the enlarged bushing socket areas 12d, 120. or abut against the bushing bottom areas 12d, 12d. The bushings 12. are each preferably made from a displaceable, flexible insulator maten'al which is preferably a synthetic, such as, silicone rubber.

After the bushings 12 are compressed during the riveting operation whereby the components of the terminal assembly 10 are secured in unitary assembly together, upper and lower bulged bushing portions 20, 21 and 20, 21 are created. These bulged portions are engaged with the upper and lower insulator edges or shoulders He, He and 11 11 The upper bulged portions are created as a consequence of the terminals coacting with the pins 17, 17 to displace material over the insulator edges 11a, He. The lower bulged portions are created by the coaction of collar edges 15c, 15c with the pins 17, 17 and the bushings 12, 12 to displace the bushing material into engagement with the beveled insulator edges 11], 11 (FIGURE 4).

The cups 11a are provided with beveled or rounded bottoms 11g and the connecting section 11b is spaced from the cover plate 15 as are the rounded bottoms 11g thus enabling the plate 15 to be painted, cleaned, and subjected to other operations of this type. By spacing the mounted bottoms 11g and the bottom of the linking section 111) from the plate 15, the terminal assembly 10 may be much more readily kept clean.

In view of the fact that the linking bushing section 11b is integral with the cups 11a, relative movement of the cups 11a with respect to one another is positively prohibited and the likelihood of open or short circuits or damage to the hermetic seal is materially reduced.

In FIGURE is shown a modified form of the inven tion and it will be noted the same reference numerals have been used to identify identical or substantially identical elements which have been previously described. In the present instance, the reference numeral a indicates generally a cover assembly and the reference numeral 10a indicates generally a terminal assembly which is a part of the cover assembly Mia. The other elements of the cover assembly 1th: are the previously described insulator 14 and the plate 15.

The terminal assembly 10a is substantially identical to the terminal assembly 10 except the configuration of bushings 12 as compared to the bushing 12 shown in the first embodiment, have been modified. Also the relationship of the cover insulator 14- and the cover plate 15 with respect to the bushings 12' has been altered.

The bushings 12' each include a bushing shank portion 12a which extends through the cup 1111. The plate 15 is carried on the bushing shoulder 12b. After each of the bushings 12' has been assembled with the cover plate 15, each of the bushing shank portions 12a are telescoped into the associated bushing insulator passage 11d with a portion of the bushing shank portion 12a being disposed within the insulator socket area Me.

The shank pin portion 17a is then telescoped through each of the terminal pin passages provided in the base terminal leg, as previously described. This sub-assembly is then guided into the socket area of the cup 11a and the pin shank portion 17a is extended axially through a central tubular bushing passage The pin shank portion 17a when assembled with the bushing 12 extends the full length of the bushing shank portion and is disposed externally of the bushing adjacent a bushing bottom area 12d provided on enlarged bushing head portion 122'.

The insulator 14 is then engaged over the end of the shank pin portion 170 along with the washer 18. The pin 17 is then riveted at 19 in the same manner as previously described whereby upper and lower bulged bushing portions 29 and 21' are created. These bulged portions are engaged under tension with the upper and lower insulator edges or shoulders 11a and 11 in the same manner as previously described. In this form of the invention it will be appreciated therefore that the insulator 14 and the plate 15 are maintained in spaced relationship on opposite sides of the bushing head portion 120'. In the first form of the invention they were secured on the same side of the bushing head portion 120.

In FIGURE 6 is shown still another modified form of the invention and the reference numeral 30 indicates generally a capacitor cover assembly and the reference numeral '30 indicates generally a terminal assembly.

This embodiment is similar to FIGURE 5 except that the realtionship of the pin with respect to the elements is slightly modified.

The terminal assembly 30 includes a fastener or a pin 31 which has a pin shank portion 31a carried within the bushing 12'. The pin 31 is also provided with a pin head portion 31b which is disposed below the cup 11a instead of being disposed within the cup socket area 11c as was the case with the other forms.

In the assembly of the elements of the cover assembly 30, the insulator is stacked on the pin in such a way that it abuts against the head portion 31b of the pin 31. The bushing 12' is then stacked on the pin 17 and over the shank pin portion 31a along with the cover plate 15. The cup 11a is then engaged over the outside surface of the bushing 12.

In order to secure the components of the cover assembly 30' in assembly together a terminal 32 is engaged upon an upper terminal pin portion 31d. The terminal 32 includes a pair of spaced prongs 32a, 32a which are joined together by a base terminal leg 3212.

To complete the assembly of the cover assembly 30, the base terminal leg 32]) is pressed in a direction towards the pin head portion 31b so that the bulged areas 20' and 21' are created. The base terminal leg 32b is then welded at 33 to the terminal pin portion 31d to join the elements in unitary assembly.

While in all instances the terminal assembly may be assembled on a cover plate, the terminal assembly may also be mounted on another area, such as a wall for example. If the terminal assembly is part of a wall it may be stationary and the sockets would be moved against the prongs so the prongs could be engaged in the sockets. In all forms, the cups provide means for reducing the likelihood of arcing between the prongs and metal plate. In all forms, the material of the bushings is displaceable into underlying and overlying relation with respect to the plate or wall to which the terminal assembly is to be attached.

In FIGURES 5 and 6 each of the bushings prior to engagement with the associated pin or fastener is of substantially uniform cross-section along its length whereby the inside and outside diameters of the bushing are substantially the same. When the bushing in FIGURES 5 and 6 is compressed and held in place by the rivet or the weld, the material of the bushing is displaced so that a seal is created about the opening in the bottom of the cup.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

We claim as our invention:

1. A cover assembly comprised of spaced synthetic bushings each having a bushing shoulder, a cover plate carried by said bushing shoulders and having spaced cover plate collars, a one-piece terminal insulator having cups each having upper and lower insulator edges, the lower edges of said cups being mounted on said collars, the cups providing terminal insulator socket areas in which the ends of said bushings are disposed, terminals each being carried on one of said bushings in one of said socket areas and each protruding from the bushing externally of the socket area, the cups and the bushings having aligned passages and fasteners, one disposed in each of said passages of said bushings and securing one of said terminals and one of said bushings in assembly with said onepiece terminal insulator, said synthetic bushings having upper and lower bulged portions bulged outwardly against the upper and lower edges of said cups to lock and seal the bushings in assembly with said one-piece terminal insulator when said fasteners are assembled with said one-piece terminal insulator, the lower bulged portions of said bushings being disposed between the fasteners and the collars and engaged against the lower edges of said cups and with the collars protectively encasing the lower bulged portions.

2. A cover assembly comprised of spaced synthetic bushings each having a bushing shoulder, a cover plate carried by said bushing shoulders and having spaced cover plate collars, a one-piece terminal insulator having cups each having upper and lower insulator edges, the lower edges of said cups being mounted on said collars, the cups providing terminal insulator socket areas in which the ends of said bushings are disposed, terminals each being carried on one of said bushings in one of said socket areas and each protruding from the bushing externally of the socket area, the cups and the bushings having aligned passages and fasteners, one disposed in each of said passages of said bushings and securing one of said terminals and one of said bushings in assembly with said one-piece terminal insulator, said synthetic bushings having upper and lower bulged portions bulged outwardly against the upper and lower edges of said cups to look and seal the bushings in assembly with said one-piece terminal insulator when said fasteners are assembled with said one-piece terminal insulator, the lower bulged portions of said bushings being disposed between the fasteners and the collars and engaged against the lower edges of said cups and with the collars protectively encasing the lower bulged portions, said lower edges being beveled with the collars engaged against the lower beveled edges below the lower bulged portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,813,716 Thordarson July 7, 1931 2,904,622 Beronio Sept. 15, 1959 FOREIGN PATENTS 737,205 Great Britain Sept. 21, 1955 OTHER REFERENCES Publication I, G. E. Capacitors-Silicone-Sealed For Life, General Electric Review, June 1950, Advertisement on the back of the front cover page. 

